code: def test_histogram_categorical_color_op(self):
      histogram = Histogram(
          [(0, 0, "A"), (0, 1, "B"), (0, 2, "C")], vdims=["y", "color"]
      ).opts(color="color")
      msg = "ValueError: Mapping a continuous dimension to a color"
      with pytest.raises(AbbreviatedException, match=msg):
          mpl_renderer.get_plot(histogram)
  
imports: import datetime
  import numpy
  import pytest
  from holoviews.core.options import AbbreviatedException
  from holoviews.core.overlay import NdOverlay
  from holoviews.element import Dataset, Histogram
  from holoviews.operation import histogram
  from holoviews.plotting.util import hex2rgb
  from ...utils import LoggingComparisonTestCase
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 12 for calling the TestHistogramPlot obj's underlying member method code with example usage: obj.test_histogram_categorical_color_op() without return types